Currently available containers for liquids such as orange juice, milk, sour cream and liquid quiche generally are multi-ply structures of metal foil, such as aluminum foil, and polyethylene-coated bleached paperboard. The shelf life of the filled container is normally less than 14 days. During this time period the paperboard tends to absorb moisture from the contents of the container and from the surrounding atmosphere, causing the container to bulge and to feel soft to the hand. This bulging results in product returns from the retailer even though the quality of the liquid in the container is still satisfactory.
The problem of bulging is especially severe when the containers are stored in a non-frost free environment, e.g. in a walk-in refrigerator, where the relative humidity is above 90%. Increasing the thickness of the polyethylene coating does not solve the problem of moisture absorption by the paperboard, and in some cases may have a negative effect because more moisture is trapped in the board.